In comments to a group of US lawmakers, within hours of Bush warning against changing the status quo with China, President Chen Shui-bian said on Wednesday the referendum was aimed only at avoiding war.
"The topic of the defensive referendum ballot is very simple, very concrete and very important," he said, according to a videotape of the meeting handed out by his office.
"We demand the opposite side to dismantle their missiles and publicly renounce the use of force against Taiwan. And our defensive referendum also aims to avoid war and eliminate the people's fear."
Chen added he supported the status quo with China.
"We also want to maintain Taiwan's status quo," he said. "Taiwan is an independent sovereign country. As the president of the Republic of China, my duty and mission is to protect our country's sovereignty, dignity and safety and protect our current independent status to make sure it doesn't change".
"We urge the international community not to take for granted China's military threat and deployment of missiles."
China and Taiwan split at the end of the Chinese civil war in 1949, and have been diplomatic and ideological foes ever since. The United States supports Beijing's "one China" policy, but remains Taiwan's biggest ally and arms supplier.
Bush told reporters after meeting Chinese Premier Wen Jiabao on Tuesday, he opposed the referendum.
"We oppose any unilateral decision by either China or Taiwan to change the status quo. And the comments and actions made by the leader of Taiwan indicate that he may be willing to make decisions unilaterally to change the status quo, which we oppose," Bush, seated beside Wen in the Oval Office, told reporters.
"We urge the international community not to take for granted China's military threat and deployment of missiles"
His statement has marked a nuanced hardening of the usual US line that Washington does "not support" independence moves by the island.
Earlier, Taiwan's Minister of Foreign Affairs, Eugene Chien, said he saw no change in US policy towards the island, despite Bush's blunt warning.
"The United States' basic stance is the same as in the past. It maintains the 'one China' policy is against any side making a unilateral change in the status quo and wants a peaceful solution," Chien said.